Sedan (nuclear test)

Storax Sedan was a shallow underground nuclear test conducted in Area 10 of Yucca Flat at the Nevada National Security Site on July 6, 1962, as part of Operation Plowshare, a program to investigate the use of nuclear explosives for mining, cratering, and other civilian purposes. The radioactive fallout from the test contaminated more US residents than any other nuclear test. The Sedan Crater is the largest human-made crater in the United States and is listed on the National Register of Historic Places.

Effects

Sedan was a thermonuclear device with a fission yield less than 30% and a fusion yield about 70%. According to Carey Sublette, the design of the Sedan device was similar to that used in the Bluestone and Swanee tests of Operation Dominic conducted days and months prior to Sedan respectively, and was therefore not unlike the W56 high yield Minuteman I missile warhead. The device had a diameter of , a length of , and a weight of . The blast caused seismic waves equivalent to an earthquake of 4.75 on the Richter scale. but it dropped to 500 mR per hour after 27 days. with radiation levels at 35 mR per hour after 167 days. The crater was listed on the National Register of Historic Places on March 21, 1994.

Salsola tragus, also known as tumbleweed, is the primary plant species growing in the crater along with some grasses. Analysis in 1993 observed that the original perennial shrubs once living there had shown no recovery.

Statistics

right|thumb|Observation decks at Sedan Crater

• Maximum depth The explosion created fallout that affected more US residents than any other nuclear test, exposing more than 13 million people to radiation.

Of all the nuclear tests conducted in the United States, Sedan ranked highest in overall activity of radionuclides in fallout. The test released 880,000 curies (33 PBq) of radioactive iodine-131, an agent of thyroid disease, into the atmosphere. Sedan ranked first in percentages of these particular radionuclides detected in fallout: ¹⁹⁸Au, ¹⁹⁹Au, ⁷Be, ⁹⁹Mo, ¹⁴⁷Nd, ²⁰³Pb, ¹⁸¹W, ¹⁸⁵W and ¹⁸⁸W. Sedan ranked second in these radionuclides in fallout: ⁵⁷Co, ⁶⁰Co and ⁵⁴Mn. Sedan ranked third in the detected amount of ²⁴Na in fallout. In countrywide deposition of radionuclides, Sedan was highest in the amount of ⁷Be, ⁵⁴Mn, ¹⁰⁶Ru and ²⁴²Cm, and second highest in the amount of deposited ^127mTe.

Conclusions

The Plowshare project developed the Sedan test in order to determine the feasibility of using nuclear detonations to quickly and economically excavate large amounts of earth and rock. Proposed applications included the creation of harbors, canals, open pit mines, railroad and highway cuts through mountainous terrain and the construction of dams. Assessment of the full effects of the Sedan shot showed that the radioactive fallout from such uses would be extensive. Public concerns about the health effects and a lack of political support eventually led to abandonment of the concept. No such nuclear excavation has since been undertaken by the United States, though the Soviet Union continued to pursue the concept through their program Nuclear Explosions for the National Economy, particularly with their 140 kiloton Chagan (nuclear test), which created an artificial lake reservoir (see Lake Chagan).

Diplomatic issue with Sudan

On March 2, 2005, Ellen Tauscher, a Democratic member of the U.S. House of Representatives from California, used Sedan as an example of a test which produced a considerable amount of radioactive fallout while giving congressional testimony on the containment of debris from nuclear testing. However, the name "Sedan" was incorrectly transcribed as "Sudan" in the Congressional Record.

Within days of the error, the international community took notice. Sudanese officials responded by stating that "the Sudanese government takes this issue seriously and with extreme importance". The Chinese Xinhua General News Service published an article claiming that the Sudanese government blamed the U.S. for raising cancer rates among the Sudanese people. Despite the U.S. embassy in Khartoum issuing a statement clarifying that it was a typographic error, Mustafa Osman Ismail, the Sudanese Foreign Minister, stated his government would continue investigating the claims.

See also

• Chagan (nuclear test)
• Peaceful nuclear explosion
• Greenhouse Item

References

External links

• US government movie about the Sedan test
• Virtual-Reality tour of Sedan Site
• Sedan Crater at the Online Nevada Encyclopedia
• Sedan Nuclear Test – Original Military Film – YouTube
• Nevada National Security Site History – Sedan Crater (PDF)
• The Nuclear Sedan Crater of Nevada